This invention relates to an improved spark plug and, more particularly, to mechanisms for relieving a portion of the normal compression forces during the starting operation of an internal combustion engine.
Because of the normal compression forces obtained in conventional internal combustion engines it is often difficult for some persons to manually start such engines (e.g. on conventional lawn mowers, snow blowers, etc.) using a normal recoil starter. Although pressure relief or bleed valves are commercially available which are designed to vent a portion of the gases from the cylinder during the starting operation of the engine, it is necessary to drill a separate hole or aperture in the cylinder head in order to accommodate the pressure relief or bleed valve. This technique, of course, does not lend itself to practical retrofitting on engines already in the hands of consumers.
The present invention provides means for relieving the normal compression in an internal combustion engine so that the starting operation is much easier, for example, for children and elderly persons. The apparatus of the invention is designed such that any conventional engine may be easily and readily retrofitted with such pressure relief means.